Enabling some extra logging options on MySQL is useful for temporary close analysis of what is actually going on with your server and applications.
Logging Slow Queries
To switch on the logging of queries which take a long time (default 10 seconds) enter the following line into my.cnf:
[mysqld]
log-slow-queries
This will give details on long queries typically in the following log file:
/path/to/mysql/data/hostname-slow.log
Or we can specify the log file location in my.cnf as follows:
log-slow-queries = /var/log/mysql/mysql-slow.log
Logging All MySQL SQL Queries
If you want to check up on the actual SQL queries performed on MySQL logging can be switched on in your my.cnf file as follows:
log = /var/log/mysql.log
Beware though that this is a big performance hit so should only be used when necessary.
